array_to_xml.php

<?php

//function definition to convert array to xml
function array_to_xml($array, &$xml_user_info, $name = null) {
	foreach($array as $key => $value) {
		if(is_array($value)) {
			if(!is_numeric($key)){ //just for associative array
				array_to_xml($value, $xml_user_info, $key);
			}else{ //just for indexed array
				$subnode = $xml_user_info->addChild($name);
				array_to_xml($value, $subnode);
			}
		}else {
			$key = ($name ? $name : $key); //if it's from a pure indexed array, use the name of the key
			$xml_user_info->addChild($key,htmlspecialchars($value));
		}
	}

	return $xml_user_info;
}


//EXAMPLE
$users_array = array(
	"total_users" => 3,
	"lista" => array(
		"ciao",
		"ciao2"
	),
	"users" => array(
		array(
			"id" => 1,
			"name" => "Smith",
			"address" => array(
				"country" => "United Kingdom",
				"city" => "London",
				"zip" => 56789,
			)
		),
		array(
			"id" => 2,
			"name" => "John",
			"address" => array(
				"country" => "USA",
				"city" => "Newyork",
				"zip" => "NY1234",
			)
		),
		array(
			"id" => 3,
			"name" => "Viktor",
			"address" => array(
				"country" => "Australia",
				"city" => "Sydney",
				"zip" => 123456,
			)
		),
	)
);

//creating object of SimpleXMLElement
$xml_user_info = new SimpleXMLElement("<?xml version=\"1.0\"?><user_info></user_info>");

//function call to convert array to xml
array_to_xml($users_array,$xml_user_info);

//saving generated xml file
$xml_file = $xml_user_info->asXML('test.xml');

text.xml

<?xml version="1.0"?>
<user_info>
    <total_users>3</total_users>
    <lista>ciao</lista>
    <lista>ciao2</lista>
    <users>
        <id>1</id>
        <name>Smith</name>
        <address>United Kingdom</address>
        <address>London</address>
        <address>56789</address>
    </users>
    <users>
        <id>2</id>
        <name>John</name>
        <address>USA</address>
        <address>Newyork</address>
        <address>NY1234</address>
    </users>
    <users>
        <id>3</id>
        <name>Viktor</name>
        <address>Australia</address>
        <address>Sydney</address>
        <address>123456</address>
    </users>
</user_info>